J. Nannoplankton Res. 28 (1), 2006, pp.1-16 © 2006 International Nannoplankton Association
ISSN 1210-8049 Printed by Cambridge University Press, UK1

Stereo-microscopy of coccolithophores - modernapplications for imaging and morphological analysis
Harald Andruleit
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover, Germany; h.andruleit@bgr.deMarkus Geisen
Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany

Sabine Stäger
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover, Germany
Manuscript received 31st October, 2005; revised manuscript accepted 6th December, 2005

Abstract We present selected stereo-images of living coccospheres to give new insights into the spatial appearance of coccolithophores. One picture was made before and one after tilting the scanning electron microscope stage.
The images were turned to red and green, respectively, and combined. The complete 3D image can be viewed with
red-green glasses. The possibilities of using stereo-microscopy as the basis for 3D mathematical models of coccospheres and coccoliths are discussed.
Keywords Stereo-image, coccolithophores, 3D image, red-green anaglyph, mathematical model
1. Introduction
Palaeontology in general, and micropalaeontology in particular, depend on the visual examination of fossils fortaxonomic identification and morphological analysis.
Once the electron microscope was developed, the investigation of calcareous nannoplankton was greatlyenhanced, gaining information on the structure and morphology of isolated coccoliths and complete coccospheresthat could not be determined from light microscope study(e.g. Halldal & Markali, 1955). An electron microscope
has both a much higher magnification than a light microscope and a greater depth of field. Together, these allow asignificantly improved impression of spatial dimensions.
Stereo-microscopy has been applied, occasionally, tocalcareous nannoplankton for a long time. Hay et al.
(1967) illustrated holotoypes of Gephyrocapsa
caribbeanica and Fasciculithus tympaniformis using
stereo-pairs. These classic stereo-pairs are difficult toview, and so, probably for the first time, Geisen et al.
(2000) applied the red-green anaglyph method to nannoplankton images. With digital systems, the images are justas easy to produce as conventional stereo-pairs and are
more comfortable to view. However, it requires colour
printing and the images are meaningless without the special glasses (therefore a pair of glasses is attached to thisissue). Geisen et al. (2000) presented a number of 3D
illustrations of coccolithophores, and underlined thepotential from the analysis of such structures for futureapplications. More recently, illustrations of mechanicalmodels, based on 2D images transferred into 3D structures, were shown as a poster at INA10 (Lisbon, 2004) byJ. Geisen, M. Geisen, C. Hamm & J. Young.
Here, we present selected stereo-images of living coc-cospheres to give new insights into the spatial appearanceof coccolithophores. In addition, we discuss the possibilities of using stereo-microscopy as the basis for 3D models of coccospheres and coccoliths.
2. Procedure and images
For the present investigation, we used a set of plankton
samples from the eastern Indian Ocean off Java(Indonesia), collected during the RV SONNE Cruise
SO139 in February, 1999. No special treatment was necessary to prepare the samples. The images were takenwith a Sirion 200 field-emission scanning electron microscope (SEM) of the Dutch company FEI. After selecting aspecimen, a standard image was made. A second image
was taken after tilting the SEM stage by about fivedegrees. (This normally time-consuming procedure canbe facilitated if the SEM is equipped with an eucentricstage.)
Following the red-green anaglyph method, the twopictures were turned to red and green, respectively, andcombined. This was done with the software XL Pro (SoftImaging System). Special attention was paid to let thezero-level coincide with the page surface. The complete
3D image can then be viewed with red-green glasses. Ittakes approximately ten times longer to produce a 3D
image than a normal SEM image.
The following figures (Plates 1-12, Figures 1) show
selected examples of living coccolithophores as 3D
images. Additionally, standard SEM photos are shown(Plates 1-12, Figures 2). Identification followed Young etal. (2003). Digital images are archived in theBundesanstalt für Geowissenschaften und Rohstoffe(BGR) palaeontology image database. Stubs are stored in2Andruleit, Geisen, Stäger

the BGR SEM collection.
For the construction of a 3D mathematical model, wechose the species Calcidiscus quadriperforatus. The samples were collected during the RV Hesperides cruise
MATER-2, Leg 3, to the Alboran Sea, western
Mediterranean. Images were taken with a Philips fieldemission SEM XL-30 FEG. Stubs are stored at theNatural History Museum, London.
3. 3D mathematical models - futureapplications and prospects
Stereo-pair images are in common use in geography, geology and satellite- or air-based mapping. Software is readily available to construct 3D models, such as landscapemodels from two dimensional images. Recently, such programs have become available for topomicroscopicalanalyses (Mex Alicona). This software allows the construction of 3D mathematical models of objects fromstereo-pair images, and will enable the more complex
coccolithophore geometries to be parameterised as well.
Here, we demonstrate the results obtained with thissoftware, using stereo-images of a Calcidiscus quadriperforatus combination cell (Figure 1). Our future work willconcentrate on gaining a substantial database of geometries of coccolithophores. This data can then be used toproduce computer models of coccoliths and coccolithophores (Figure 2), and applied to test light refraction,mechanical stability, and to accurately determine speciesspecific calibrations for coccolith size-weight relationships. We believe that 3D imaging, and its combination
with other techniques, will enhance our understanding of
the functional morphology of coccolithophore cell covers,
coccolithophore ecology, export production, and calcite
flux.
Acknowledgements
We thank the masters and crews of the research vessels for their
help in retrieving the plankton samples. The constructive criticism and valuable comments of Jackie Lees, Richard Jordan andJeremy Young are thankfully acknowledged.

References
Geisen, M., Jones, C., Shaw, M. & Young, J. 2000. Threedimensional imaging of coccoliths and coccospheres.
Abstract for poster presented at the 8th Conference of theInternational Nannoplankton Association, 11th-15th
September, 2000, Bremen, Germany, Journal ofNannoplankton Research, 22: 100.
Halldal, P. & Markali, J. 1955. Electron microscope studies on
coccolithophorids from the Norwegian Sea, the Gulf Stream
and the Mediterranean. Avhandlinger Utgitt av det Norske
Videnskaps-Akademi i Oslo, 1: 5-30.
Hay, W.W., Mohler, H.P., Roth, P.H., Schmidt, R.R., Boudreaux,J.E. 1967. Calcareous Nannoplankton Zonation of the
Cenozoic of the Gulf Coast and Caribbean-Antillean Area
and Transoceanic Correlation. Transactions of the Gulf
Coast Association of Geological Societies, 17: 428-480.
Young, J., Geisen, M., Cros, L., Kleijne, A., Sprengel, C.,
Probert, I. & Østergaard, J.B. 2003. A guide to extant coc-colithophore taxonomy. Journal
Research, Special Issue, 1: 125pp.

ofNannoplankton

Stereo-microscopy of coccolithophores

3Plate 1
Rhabdosphaera clavigera

Figure 1: Image # 5049
5µm
Figure 2: Image # 5048

4Andruleit, Geisen, Stäger

Plate 2Oolithotus antillarum - cluster of coccospheres

Figure 1: Image # 4980
5µmFigure 2: Image # 4979

Stereo-microscopy of coccolithophores

5Plate 3
Coronosphaera mediterranea

Figure 1: Image # 5082
5µm
Figure 2: Image # 5081

Andruleit, Geisen, Stäger6Plate 4
Gephyrocapsa oceanica

Figure 1: Image # 4739
5µm
Figure 2: Image # 4738

Stereo-microscopy of coccolithophores

7

Plate 5
Acanthoica quattrospina

Figure 1: Image # 5061
2µm
Figure 2: Image # 5060

8Andruleit, Geisen, Stäger

Plate 6
Umbellosphaera irregularis

Figure 1: Image # 5059
2µm
Figure 2: Image # 5058

Stereo-microscopy of coccolithophores

9

Plate 7
Discosphaera tubifera

Figure 1: Image # 4987
5µm
Figure 2: Image # 4986

10Andruleit, Geisen, Stäger

Plate 8
Umbilicosphaera sibogae

Figure 1: Image # 5038
5µm
Figure 2: Image # 5037

Stereo-microscopy of coccolithophores

11

Plate 9
Alisphaera gaudii

Figure 1: Image # 5055
2µmFigure 2: Image # 5054

Andruleit, Geisen, Stäger

12

Plate 10
Syracosphaera exigua

Figure 1: Image # 4985
2µm
Figure 2: Image # 4984

Stereo-microscopy of coccolithophores

13

Plate 11
Florisphaera profunda

Figure 1: Image # 5045
2µm
Figure 2: Image # 5044

Andruleit, Geisen, Stäger

14

Plate 12
Umbilicosphaera hulburtiana

Figure 1: Image # 5036
2µm
Figure 2: Image # 5035

Stereo-microscopy of coccolithophores

15BACDEFFigure 1: A) Calcidiscus quadriperforatus combination coccosphere (green channel). B) Stereo-pair of C. quadriperforatus. C) 3D topomicroscopical image constructed from 2D stereo-pairs with a 4˚ angle. Note that this software allows easy acquisition of 3D data and models from SEM images
for the first time. D) Height model of the same image. E, F) Elevation models for different transects. Note that angles between plates can be measured directly. Data obtained with this method can form the basis for models, as shown in Figure 2

16Andruleit, Geisen, Stäger

Figure 2: SEM image of a Calcidiscus cell (left) and corresponding 3D mathematical model (right). Such reconstructions can be used to test hypotheses related to the functional morphology of coccospheres, such as light refraction or concentration, mechanical stability, and buoyancy regulation.
At the same time, they allow for a precise and fast estimation of the species-specific calcite content, which is important in estimating calcite exportproduction